Asiakkaan nimi

A true case in our apartment house:  There was a significant fire downstairs of the apartment in local pizzeria/kebab house. The fire was taken over quite soon by local fire department. As a result of the fire, the damages were analyzed from fire itself, the dust and water used to take over the fire.

Our apartment is located in upper level, but still the smell of smoke easily covered the whole stairs and reached the flat for living. As a result – all the bottom floor rooms were inspected specifically for possible damages. Our flat´s stock room is located in the floor were the fire was heaviest. All the lockrooms were studied for possible damages. They found a lot of worms from our textile pouches in our stock, and some example pieces of worms were taken. We took immediately microscopic images out of them with KeepLoop. The images were send to the city specialist in insects. He came back with analysis:

“This worm is born from a Beetle, Reesa Vespulae. It is not harmful in standard conditions, even though the name in some languages means different. This worm is extremely harmful especially in museums and locations, where dried insect are collected. In case you don’t owe any butterfly collection or similar, there should be no danger. No additional prevention is needed.”

Summarize: The analysis came instantly from the specialist and from the picture taken by KeepLoop mobile microscope together with our mobile phone. The connection to fire is still unclear and under investigation, but we are satisfied from the prompt analysis from the circumstances of possible worm attack in our stock against textiles.

KeepLoop has opened an image bank of pictures taken with the microscope device. The site is available in Picasaweb for all users and the microscopic images can be used freely just by mentioning the source. Users can also download to the image bank their own pictures taken with the KeepLoop device.

Currently the bank contains around 170 images, but this number is increasing fast as new objects are been photographed. The microscope device is so easy to carry around that all the people in the KeepLoop staff have them in their pockets wherever they go. Every time that an interesting surface, texture or microscopic object is seen, an image is taken and the best ones are added to the site. As the customer base and number of images in the bank increase, the site will provide a source of reference pictures or just a good place to look for microscopic images.
 
There are several different categories in the bank, which makes it easier to find the pictures you are most interested in. The microscope product is mainly aimed for professional users working e.g. in the printing industry, but due to the high enthusiasm shown by people outside the main target groups, some general interest categories like “plants” and “animals” have also been added. As an example, the picture below shows one infamous Finnish mosquito killed by our own CEO Ali Toivola during the last trade-fair held in Ylämaa (south-east Finland), where KeepLoop was present.

Microscopic image of a Finnish mosquito

Link to the image bank: https://picasaweb.google.com/106438690093540963901

KeepLoop microscope has been designed to work with most mobile devices that have a camera. Most of the small lenses that you find from miniature cameras of mobile phones, tablets or laptops have quite similar properties. Due to the strict size restrictions (mainly height) they all have focal lengths in the approximate range of 2 mm – 5 mm and the pupil sizes are between 0.5 mm and 2 mm. This similarity has made it possible for us to develop the universal extreme-macro-lens, which is the heart of KeepLoop device. The lens has been designed is such a way that there is lots of tolerance on the distance between the lens and camera pupil. This makes it possible to take pictures with cameras that are fairly deep inside the master device (e.g. Nokia N82) and with cameras that are positioned close to the back surface of the device (e.g. Samsung Galaxy S II). Optically the KeepLoop microscope is designed to work with all miniature cameras and the main challenge is how to attach the lens to the back of differently shaped devices.

As the master device cameras are not all the same, the features that determine the exact optical performance characteristics also vary. In order to test the compatibility of our microscope with different mobile phones, we conducted a trial where we used KeepLoop with eleven camera phones. The ultimate resolution test was to image a grating made for calibrating microscopes (Thorlabs' R1L3S2P 1 mm Stage Micrometer). The grating had a 1 mm scale divided into 100 line-pairs, which means that the widths of the single lines, and the spacing between the lines, was only 5 µm. The results showed that all of the 8MP cameras were able to resolve even the single lines, but there were clear differences on how reliable the imaging was. One example of images taken with Samsung Galaxy S II, Nokia N7 and iPhone 4S is shown below.

Some of the 5MP phones (e.g. Huawei U8800) were almost able to reproduce the grating image, but generally the sharpness was not as good and around 10 µm resolution can be expected with these devices. This is no surprise when the pixel mapping from the object to the image is taken into account. With the 8MP cameras, one image pixel corresponds to circa 2.5 µm feature size on the object, whereas with the 3MP - 5MP cameras one pixel is closer to 3 µm - 4 µm feature size. This difference means that when two 8MP camera pixels are put side-to-side they can be fitted inside those 5 µm grating lines, but with the 3MP - 5MP sensors this is not possible. The 8MP cameras are actually imaging the grating lines at the theoretical resolution limit (Nyquist frequency) of the image sensor. This also means that the signal processing made to the raw image is of high quality and the processing may actually explain the most of the resolution differences between cameras with the same pixel count.

KeepLoop has now developed the world’s first digital mobile 3D microscope, which is capable of measuring surface micro topography. The whole system is portable and software operation intuitive with the device touch screen controls.

The KeepLoop 3D microscope measures surface topography from an area of around 5 mm x 5 mm and ~10 µm resolution with a machine vision technique called photometric stereo. By combining three images with different illumination, the 3D data is calculated with a special algorithm. Calculations and user interface software were developed first on Android 4.0 operating system. The system is based on custom-made optoelectronics device that attaches to the master device and forms the 3D microscope together with the proprietary software.

Sample image: A 3D gradient image from 5 euro cent coin

The fully functional mobile 3D microscope prototype is demonstrated at the Drupa trade fair held in Düsseldorf May 3 - 16, 2012. KeepLoop booth is located in Hall 7.1, Stand D51.

The world's first digital 3D mobile microscope is developed on Android 4.0 

One (not so sunny) morning I opened my email and there was a question: Does KeepLoop work with Nokia N8? Well, how should I know? I left my desk and walked to the other side of the office. I knocked on the door and opened it. There was my boss (always sunny) sitting in his chair and Nokia N8 was lying on the table. I loaned the N8 for test use only. (No, I’m not gonna play Angry Birds.) 

I returned to my desk and started the test. The challenge is that the back of N8 isn’t flat. The lens is couple of millimeters higher than the rest of the back cover.  At first I put one metal sticker on the back but that was definitely too low to keep the KeepLoop attached to the N8. So I add another sticker on the top of the first one and that worked perfectly.  There is also a hard plastic bracket or cover available for the N8 which makes the back of the phone flat. With the bracket N8 is just like any other phone and works great with the KeepLoop.  

The result of my test is that Nokia N8 works fine with KeepLoop. Now I have to return the N8 to my boss and hope that he doesn’t realize that I’ve beaten his Angry Birds record. ©

KeepLoop lens can’t be directly compared to a standard microscope lens. The main reason for this is the fact that it is only one part of a whole optical system, which is formed when our device is placed on top of the master device camera optics. Properties like focal length, f#, FOV (field of view) and optical power of the whole system are determined by the combination or our lens and the master device objective.

Optical magnification of the KeepLoop extreme-macro-lens in combination with the device camera objective has the approximate ratio of 1:2. This means that if the camera sensor has pixel size of e.g. 1.4 µm, the area that one single pixel sees on the imaged object is roughly double in size, 2.8µm. Aberrations in the whole optical system blur the image, so the actual resolution is much less than what would be expected from the theoretical optical magnification value alone. It is also not possible to reliably resolve features that fill only one pixel, as there is the possibility that the feature falls directly between two pixels and they both show the same information. Theoretically, two side-by-side pixels can be seen as adequate, but 3 - 5 pixels are needed for reliable outcome. In practice, the KeepLoop lens can resolve object features that are below 10 µm (0.01 mm) in size. The final resolution is determined by the pixel size and optical properties of the camera objective. Current high-end mobile cameras have smaller pixels (still above 1 µm) as well as better optics and the resolution with the microscope can be as good as ~6 µm.

As KeepLoop is used only for digital imaging, the magnification of our microscope is mainly determined by the display device. When the digital image recorded with the CMOS sensor is displayed on a larger screen, the final magnification is determined purely as the ratio between the imaged area on the object and the visible area on the screen. The extreme-macro-lens typically makes a good image over an area, which is between 2 – 4 mm wide and 1.5 – 3 mm high. Example: If an object area of 3 mm x 4 mm is imaged with the mobile microscope and the image is displayed with a 10” tablet, the magnification of the image is around 50x. But if the same image is displayed with a full HD projector showing a 100” image, the magnification can be as high as 500x. As the digital image is displayed on a big screen, the eye sees also the enlarged matrix of pixels. This means that the significant factor is not the magnification, but the quality of the optics and mainly resolution of the lens system.

One problem commonly associated to microscopes is the shallow depth of field (DOF). The larger the magnification, the smaller the DOF. This problem is emphasized in portable and hand-held devices where the distance from microscope optics to the imaged object is difficult to keep constant due to shaking of awkward positioning of the device. In KeepLoop this problem is solved by fixing the distance between optics and object with the mechanical design of the device. The KeepLoop module can simply be placed on top of the imaged surface and the lens is always at the right focus distance. This makes the device very easy to use and reliable, while still keeping it light weight and portable.

A standard mobile phone or laptop fixed focus camera is designed to image distant objects. The purpose of KeepLoop device is to transform the standard camera objective into an extreme close-range lens. The design of the KeepLoop optics conforms to the common camera lens types and it also has a fixed focus distance. If the mobile phone used with the module has an autofocus (AF) camera, this functionality can be used with KeepLoop in order to extend the DOF. The AF systems moves the camera lens up and down in front of the camera sensor, but as this movement is confined to the built-in camera module, it doesn’t interfere with the microscope optics. So overall, the KeepLoop device is insensitive to the type of camera module and it can be used with both fixed focus and autofocus cameras.